Air-feeding device for oil-burners



May 8, 1962 E. SCHWANDER AIR-FEEDING DEVICE FOR OIL-BURNERS Filed Dec. 24, 1959 rlll United States Patent 3,033,271 AIR-FEEDING DEVICE FOR ()IL-BURNERS Erwin Schwander, Reichshoifen-Usines, France, assignor to Societe dEtude de Vehicules S.E.V., Reichsholfen- Usines, France Filed Dec. 24, 1959, Ser. No. 861,902 Claims priority, application France Dec. 31, 1958 2 Claims. (Cl. 1581.'5)

The present invention relates to an air-feeding device for oil-burners.

In almost all oil-burners the combustion air or a fraction of said air is fed through a pipe of a circular crosssection, arranged coaxially with reference to the atomizing cone. For practical and technical reasons, the airfeedi-ng pipe can be only of a comparatively reduced length, so that it is necessary for the feeding of air to associate it with a pipe forming therewith an angle of 90 or an obtuse angle. This manner of operating leads to serious drawbacks.

It is known, on the other hand, that it is important, in the case of burners having a high efiiciency, wherein the fuel is to burn inside a small volume and with an excess of air reduced to a minimum, that the combustion of fuel in an equatorial section of the atomizing cone must be as uniform as possible; the distribution of the air fed towards the combustion cone must be also as uniform as possible in an equatorial area.

It should also be remarked that the uniform distribution of the fuel is outside the scope of the present invention, which concerns only the proper distribution of the air.

It has already been proposed at various times to en sure, in the available burners, a uniform distribution of the air by providing therein arrangements which often served other purposes.

It is quite impossible to incorporate such arrangements in burners, which are disclosed in the French Patent 787,- 683, or in the US. Patent 2,440,491. It is true that certain burners exist which may be provided with the arrangements referred to, but the efficiency of such arrangements remains always doubtful, unless the equatorial distribution of the air at the input is already very uniform.

It is one object of the present invention to provide an air-feeding device for oil-burners which assures in bumers, fed with air along a path perpendicular to the axis of the burner extending at a small distance from the latter, an excellent distribution of the air input in an equatorial plane.

It is another object of the present invention to provide an air-feeding device for oil-burners which consists in surrounding the actual burner with a coaxial cylinder of a comparatively large diameter and of a comparatively reduced width, and in which the air enters the outer wall of the cylinder in a direction which is substantially perpendicular to that of the burner axis, the cylinder enclosing partitioning means through which air is fed to the burner in a radial direction and with a uniform equatorial distribution.

The fact should be stressed that such a uniform distribution of the air cannot be ensured through an input spiral serving generally for inputs into blowers, pumps and the like, and such spirals are unsuitable in the case of burners, the load of which is subjected to frequent modifications.

With these and other objects in 'view, which will become apparent in the following detailed description, the present invention will be clearly understood in connection with the accompanying drawing, in which:

FIGURE 1 is a vertical section of a preferred embodi- 3,033,271 Patented May 8, 1962 "ice ment of an air-feeding device for oil-burners along the lines 1--1 of FIG. 2'; and

FIG. 2 is a horizontal section thereof along the lines 2-2 of FIG. 1.

Referring now to the drawing, and in particular to FIGS. 1 and 2, the actual burner comprises a tube or inner casing 1 associated coaxially with the central fuelfeeding pipe 2 and with the atomizing nozzle 3 at the end of the latter. The cone formed by the atomized fuel is illustrated in dot-and-dash lines and is designated by the reference letter C. The burner is disposed at the center of an outer fiat, cylindrical casing 4 into which the outer air enters through a radial pipe 4 opening into the outer wall of the cylindrical casing 4, the air entering finally axially into the inner casing 1 through an annular slot 5 formed between the rear end of the inner casing 1 and the rear wall of the casing 4. The cylindrical casing 4 is subdivided inwardly by a number of coaxial walls 6, 7, 8 and 9 into a plurality of annular chambers communicating with each other by means of ports 10 formed in the mentioned walls. There are two ports provided in the wall 6, four ports in the wall 7 and eight ports in the wall 8, whereas for the innermost wall 9, the ports are replaced by a single annular slot 11. Furthermore, the ports in any two successive walls are displaced in a symmetrical manner with reference to one another, while they are alternatingly provided in the upper half and in the lower half of the successive walls. Instead of such ports, it is also possible to provide passageways extending throughout the width of the wall. Similarly, it is also possible to substitute for said ports slots extending throughout the periphery of the walls and provided alternatingly in the upper section and in the lower section of the successive Walls inside the cylindrical casing 4.

Experiments made with a burner thus designed have shown that it provides an exceptionally high uniformity of equatorial distribution of the air inside the burner tube 1, in all cases, even when the load on the burner is subjected to large modifications. Furthermore, a burner provided with the air-feeding means according to the present invention brings about the advantage that the cylindrical casing 4 surrounding the burner may serve, it required, as an air-cooled cover for an apparatus to be heated by the burner.

Obviously, many modifications may be brought to the embodiment disclosed by way of example, without widening the scope of the invention as defined in the accompanying claims.

I claim:

1. An air-feeding device for oil-burners comprising an inner casing of small diameter and adapted to receive an atomizing nozzle and a fuel feeding pipe, an outer fiat cylindrical casing coaxially disposed around said inner casing and of short width, said outer casing having a front wall, a rear wall and a peripheral cylindrical wall, the front end of said inner casing projecting through and beyond said front Wall of said outer casing, the rear end of said inner casing terminating short of and spaced apart from said rear wall of said outer casing to define an annular slot therebetween, a radial pipe opening into said peripheral cylindrical wall substantially perpendicularly to the longitudinal axis of said outer casing and adapted to feed combustion air into said outer casing, a plurality of coaxial walls of inwardly diminishing diameter spaced apart from each other and being disposed between said peripheral cylindrical wall of said outer casing and said inner casing to provide a plurality of annular chambers, at least one port in each of said coaxial walls angularly set-oil relative to the ports in the adjacent walls, thereby feeding said combustion air fromsaid radial pipe successively through each of said annular chambers at great speed and radially from each of said annular chambers to the next inner annular chamber and finally through said annular slot axially through said inner casing, the area and distribution of the ports being such that said great speed of said combustion air diminishes towards said inner casing and said combustion air is fed equally over the entire periphery of and into said inner casing.

2. The device, as set forth in claim 1, wherein an innercoaxial annular wall surrounds said inner casing and extends from said rear wall of said outer casing short of said front wall of the latter, to define an annular slot between said front wall of said outer casing and the front end of said inner coaxial annular wall.

References Cited in the file of this patent UNITED STATES PATENTS Kemp Oct. 12, Tucker July 4, Reid Apr. 12, Andrews d. Feb. 15, Nagel Sept. 26, Patterson Jan. 30, Anderson Apr. 13, Hogberg ct a1. Jan. 20,

FOREIGN PATENTS Great Britain Nov. 2, 

